@article{GDZPPN002082780, title = {On two characteristic properties of Euclidean norms.}, journal = {Elemente der Mathematik}, volume = {46}, year = {1991}, pages = {111-115}, zbl = {0741.15020}, url = {http://dml.mathdoc.fr/item/GDZPPN002082780} }
Rummler, H. On two characteristic properties of Euclidean norms.. Elemente der Mathematik, Tome 46 (1991) pp. 111-115. http://gdmltest.u-ga.fr/item/GDZPPN002082780/